[Material] Time picker semantics updates (#67562)

packages/flutter/lib/src/material/time_picker.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 import 'dart:math' as math;
+import 'dart:ui' as ui;
 
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
@@ -355,8 +356,7 @@ class _HourControl extends StatelessWidget {
     );
 
     return Semantics(
-      hint: localizations.timePickerHourModeAnnouncement,
-      value: formattedHour,
+      value: '${localizations.timePickerHourModeAnnouncement} $formattedHour',
       excludeSemantics: true,
       increasedValue: formattedNextHour,
       onIncrease: () {
@@ -445,8 +445,7 @@ class _MinuteControl extends StatelessWidget {
 
     return Semantics(
       excludeSemantics: true,
-      hint: localizations.timePickerMinuteModeAnnouncement,
-      value: formattedMinute,
+      value: '${localizations.timePickerMinuteModeAnnouncement} $formattedMinute',
       increasedValue: formattedNextMinute,
       onIncrease: () {
         fragmentContext.onTimeChange(nextMinute);
@@ -571,7 +570,8 @@ class _DayPeriodControl extends StatelessWidget {
       child: InkWell(
         onTap: Feedback.wrapForTap(() => _setAm(context), context),
         child: Semantics(
-          selected: amSelected,
+          checked: amSelected,
+          inMutuallyExclusiveGroup: true,
           button: true,
           child: Center(
             child: Text(
@@ -589,7 +589,8 @@ class _DayPeriodControl extends StatelessWidget {
       child: InkWell(
         onTap: Feedback.wrapForTap(() => _setPm(context), context),
         child: Semantics(
-          selected: pmSelected,
+          checked: pmSelected,
+          inMutuallyExclusiveGroup: true,
           button: true,
           child: Center(
             child: Text(
@@ -1673,7 +1674,10 @@ class _HourMinuteTextFieldState extends State<_HourMinuteTextField> {
     // If screen reader is in use, make the hint text say hours/minutes.
     // Otherwise, remove the hint text when focused because the centered cursor
     // appears odd above the hint text.
-    final String? hintText = MediaQuery.of(context)!.accessibleNavigation
+    //
+    // TODO(rami-a): Once https://github.com/flutter/flutter/issues/67571 is
+    // resolved, remove the window check for semantics being enabled on web.
+    final String? hintText = MediaQuery.of(context)!.accessibleNavigation || ui.window.semanticsEnabled
         ? widget.semanticHintText
         : (focusNode.hasFocus ? null : _formattedValue);
     inputDecoration = inputDecoration.copyWith(

packages/flutter/test/material/time_picker_test.dart

@@ -329,7 +329,13 @@ void _tests() {
       includesNodeWith(
         label: 'AM',
         actions: <SemanticsAction>[SemanticsAction.tap],
-        flags: <SemanticsFlag>[SemanticsFlag.isButton, SemanticsFlag.isSelected, SemanticsFlag.isFocusable],
+        flags: <SemanticsFlag>[
+          SemanticsFlag.isButton,
+          SemanticsFlag.isChecked,
+          SemanticsFlag.isInMutuallyExclusiveGroup,
+          SemanticsFlag.hasCheckedState,
+          SemanticsFlag.isFocusable,
+        ],
       ),
     );
     expect(
@@ -337,7 +343,12 @@ void _tests() {
       includesNodeWith(
         label: 'PM',
         actions: <SemanticsAction>[SemanticsAction.tap],
-        flags: <SemanticsFlag>[SemanticsFlag.isButton, SemanticsFlag.isFocusable],
+        flags: <SemanticsFlag>[
+          SemanticsFlag.isButton,
+          SemanticsFlag.isInMutuallyExclusiveGroup,
+          SemanticsFlag.hasCheckedState,
+          SemanticsFlag.isFocusable,
+        ],
       ),
     );
 
@@ -349,9 +360,9 @@ void _tests() {
     await mediaQueryBoilerplate(tester, true);
 
     expect(semantics, isNot(includesNodeWith(label: ':')));
-    expect(semantics.nodesWith(value: '00'), hasLength(1),
+    expect(semantics.nodesWith(value: 'Select minutes 00'), hasLength(1),
         reason: '00 appears once in the header');
-    expect(semantics.nodesWith(value: '07'), hasLength(1),
+    expect(semantics.nodesWith(value: 'Select hours 07'), hasLength(1),
         reason: '07 appears once in the header');
     expect(semantics, includesNodeWith(label: 'CANCEL'));
     expect(semantics, includesNodeWith(label: 'OK'));
@@ -394,7 +405,7 @@ void _tests() {
 
     Future<void> actAndExpect({ String initialValue, SemanticsAction action, String finalValue }) async {
       final SemanticsNode elevenHours = semantics.nodesWith(
-        value: initialValue,
+        value: 'Select hours $initialValue',
         ancestor: tester.renderObject(_hourControl).debugSemantics,
       ).single;
       tester.binding.pipelineOwner.semanticsOwner.performAction(elevenHours.id, action);
@@ -460,7 +471,7 @@ void _tests() {
 
     Future<void> actAndExpect({ String initialValue, SemanticsAction action, String finalValue }) async {
       final SemanticsNode elevenHours = semantics.nodesWith(
-        value: initialValue,
+        value: 'Select minutes $initialValue',
         ancestor: tester.renderObject(_minuteControl).debugSemantics,
       ).single;
       tester.binding.pipelineOwner.semanticsOwner.performAction(elevenHours.id, action);